Current interruption indicator for electric clocks, etc.



Mam}! 1935- E. 1.. CARLSON in AL 1,995,497

CURRENT INTERRUPTION INDICATOR FOR ELECTRIC CLOCKS, ETC

Filed April 21, 1931 2* She ets$heet 1 32 mg, M g; 33

March 26, 1935.

ETC

E. L. CARLSON r AL CURRENT INTERRUPTION INDICATOR FOR ELECTRIC CLOCKS,

2 Sheets-Sheet 2 Filed ApriI 21, 1931 Patented 26; 1935- cuaaan'r nv'rsaaumou mnioa'roa, FOB.

smc'ralc omens, arc.

Elof L. Carlson and Arthur B vloole, Bristol,

Conn, assignorsto The E. Ingraham Bristol, Conn a corpol flon v C p y,

Application April 21, 1931, Serial rim-531,833

17 Claims.

This invention relates to a current-interruption indicator and particularly to a current-interruption indicator operating in response to temperature changes and while primarily designed for electric clocks, its use is not so limited, as it may be employed in combination with a variety of instruments in situations :where it' may be desired to indicate a current-interruption which may have affected the operation of an electric clock or other apparatus. I

The main object of our ,present invention is to provide a simple and reliableindicator operating in response to temperature changes which will inform the user of thefact that an interruption has taken place in the current-supply.-

A further object of-our invention is to provide a superior indicator of the type referred to which will not only visually indicate, but record an interruption in the current, so that the said interruption may benoted at a later time than that at which it-occurred.

, sists in one view thereof, of a current-interruption indicator characterized by an indicatormember; a thermomotive-member operatively connected to the said indicator-member for actuating the same; and an electric heater associated with the said thermomotive-member for activating the same;- whereby a change in temperature in the said electric heater will correspondingly affect the said thermomotive-member and cause combinations of the same to actuate the said indicator-member.

Our invention further consists in a currentinterruption indicator characterized as above and having certain .other details of description and scribed and particularly recited iii-the claims. In the accompanying drawings:

Fig. 1 is a broken perspective view of a schematic character, illustrating one form which a current-interruption indicator constructed in accordance with our invention may assume and shown in connection with a synchronous electric clock;

Fig. 2 is a corresponding view of another form which our invention may assume;

Fig. 3 isv a corresponding but less comprehenaive view illustrating still another form which our invention my assume;

will be hereinafter de- Fig. 4 is a perspective view. of-the indicatordisk shown in Fig. l; detached; and Fig. 5 is a similar -view of an indicating-disk having different markings thereon from of the preceding figure. r

The particular electric clock herein chosen for the illustration of our invention in Fig. 1 of the drawings, consists as shown, of a thermnmotive or temperature-responsive member. consisting of .a spirally-wound blmetallicfi p capable of 10 markedly changing its form to actuate an indicator in response to temperature changes, as will be hereinafter described. The said thermo- 'motive-membermaybe of any approved form. and material, and has its inner end 11 anchored in the bifurcated forward end of a stud 12 forwardly offsetting from the field-structure 13 of an electric'motor' to be more fully hereinafter described. The outer convolution member 10 terminates in a loop 14 into which is entered the rearw'ardly-exiending arm 15 of a lever 16 mounted upon the rear end of an indicator-shaft '1"! carrying at its forwardend a disk-like indicator 18 preferably having its front face adjacent its periphery, marked with suitable graduations such as those representing minute intervals and located so that the said graduations are exposed for view through an aperture 19"in' the clock-dial 20.

Also mounted upon 'the indicator-shaft 1'7 aboutmidway the length thereof is a ratchet wheel 21, the toothed periphery of which is en-; gaged by a pawl 22'mounted upon the inner end of a release-shaft 23 extending substantiallyparallel with the indicator-shaft 1! before re-. ferred to, and having its forward end projecting forwardly through the dial 20 where it is provided with a finger-button 24 for hereinafter appear. 7 g The electric motor, of which the field-structure '13 already referred to constitutes a feature, is preferably of the synchronous self-starting type I and has its respective pole-pieces 25 and 26 bifurcated and respectively provided with socalled shadingcoils 27 and 28 for producing a rotating magnetic-field for the synchronous driving of a rotor 29 mounted upon a shaft 30 and loing terminals 33 34 adaptedfor connection to 86 of the thermomotive its operation, as will 0 \cated between the pole-pieces 25 and 26, as cleara power-line supplying a sinuous electric current of carefully-regulated frequency.

The relatively-high speed of the rotor 29 is reduced to a moderate speed for operating the hourand minute-hands 35 and 36- in the wellknown manner of electric clocks, by a reduction gear-train enclosed within a. housing 37 and requiring no detailed illustration or description.

'Let it be supposed that the motor is driving the clock-hands 35 and 36 and that the indicator 18 indicates zero. Under these conditions, the heat developed by the field-coil 32, which latter acts as a heater, will maintain the thermomotive bimetallic spiral 10 at a relatively-high predetermined temperature and cause the same to maintain the indicator at zero, as shown in the drawings.

Now let it be supposed that an interruption has taken place in the supply of current to the motor. This interruption of the current will cause the field-coil 32 to cool and similarly ailfect the bimetallic spiral 10, with the result that the latter, in cooling, will slowly force its loop 14 in the direction of the arrow A, with the effect of slowly turning or thermomotively moving the indicator 18 in a clockwise direction. 7

The degree to which the, indicator 18 will be turned, as described, will depend upon the length of time that the member 10 is permitted to cool,

and hence upon the duration of the current-interruption, which latter is thus measured. Preferably; the graduations upon the indicator 18 are so spaced as to, in fact, indicate the time during which the bimetallic spiral 10 has been permitted to cool, owing to the current-interruption, and hence will serve to indicate the duration of such interruption, though, if desired, the indicator may be marked, as in Fig. 5, to merely indicate an interruption, without indicating the duration thereof.

Now, upon a resumption of the flow of current through the field-coil 32, the same will immediately rise in temperature and correspondingly afiect the bimetallic spiral 10, with the result that the same will expand and cause the looped end 14 thereof tourge the lever 15 counterclockwise, which movement, however, will be prevented by the latching eii'ect of the engagement of the pawl 22 with the ratchet-wheel 21 until such time as the current-interruption has been .noted and properly compensated'for by adjusting the hands 35 and 36 of the clock, at which time a counterclockwise tum upon the finger-button 24 will serve to temporarily disengage the pawl 22 from the ratchet-wheel 21 and permit the indicator 18 to again assume its zero position under the urge of the bimetallic spiral 10.

The current-interruption indicator above described operates in response to the temperature of the field-coil 32 which discharges the dual function of providing a magnetic field for the rotor and acting, also, as a heater for the thermomotive-member, but if desired and as shown in Fig. 2, a separate and distinct heatingelement in the form of a coil 38 may be provided closely adjacent the bimetallic spiral 10 or equivalent member. The'leads 39 and 40 of the heating-coil 38 are connected respectively. to the 1 leads 33 and 34 of the driving-motor, as clearly supply of current to the said 'coil 32 of the motor fails, it will also fail to flow through the heatingcoil as.

In the device shown in Fig. 2, instead of rigidly attaching the lever 16 to the indicator-shaft 1'7,

as in Fig. 1, the same is mounted on'the said shaft with freedom for relative oscillatory movement with respect thereto, and carries a pawl 41 pressed into engagement with the teeth of the ratchet-wheel 42 by a spring43. The ratchetwheel 42 just referred to is rigidly attached to the indicatorshaft, which latter projects through the dial 20 and is provided with a pointer 44 sweeping over an annular series of graduations 45 upon the face thereoi.

In the device of Fig. 2 just above described, when a current interruption occurs, the bimetallic thermomotive-member 10 will cool, and in so doing swing the lever 16 in a clockwise direction, with the efiect of causing the pawl 41 to idly ratchet back over the teeth of the ratchet-wheel 42 without moving the pointer 44. I

Now, upon the resumption of the current-flow the heat developed by the coil 38, or by whatever type of heater is employed, will expand the spiral 10 and cause the same to swing the lever 16 in a counterclockwise direction, and thus, through the intermediary of the pawl 41, ratchetwheel 42 and indicator-shaft 17, turn or thermomotively move the pointer 44 counterclockwise a distance sufiicient to indicate substantially the duration of the current interruption.

Now, should a second current interruption occur, prior to the manual resetting of the pointer 44 to zero, the duration of the second current interruption will be added to that of the first current interruption, and so on, so that a cumulative reading pf a series of current interruptions may be had.

It will be noted in the structure shown in Fig.

2 that, instead of the indicator being actuated as the thermomotive-member cools, as in the structure of the preceding figure, it is actuated as the thermomotive-member heats up to its normal temperature. This arrangement of parts does not give the indication of current interruption until after the same has terminated, butsince these interruptions are usually of relatively short duration, the indication is timely for all practicalpurposes.

In Fig. 3 of the drawings, we have shown a temperature-change-responsive bimetallic spiral element 46 mounted in a housing 47, provided with a heat-insulatinglining 48 and provided within its interior, just below the element 46,

with a carbon-block resistor or heating-element 49, suspended. in insulating-bushings 50 and 51 respectively mounted in the opposite side-walls of the housing, and having extending through block resistor properly connected into the circuit when the supply of current fails, the temperature of the said resistor will fall and correspondingly affect the bimetallic spiral 10 with the result that the indicator will be movedas previously described.

It will be understood by those skilled in the art that our invention may assume varied physical forms without departing from our inventive concept, and we, therefore, do not limit ourselves to the specific embodiments herein chosen for illustration, but only as indicated in the appended claims.

We claim: k

1. In a current-interruption indicator, the combination with an indicator-member; of a thermomotive-member operatively connected to the said indicator-member to thermomotively move the said indicator-member; and an electric heater associated with the said thermomotive-member for normally heating the same; whereby a change in temperature in the said electric heater will correspondingly affect the said thermomotive- I member and cause the latter to thermomotively move the said indicator-member.

2. A current-interruption indicator as defined in claim 1 and having the elements constructed and arranged to effect the movement of the indicator-member by the cooling oi. the thermomotive-member, due to current interruption.

3. A current-interruption indicator as defined in claim 1 and having the elements constructed and arranged to effect the movement oi. the indicator-member by the rise in temperature of the thermomotive-member, as the result 01' the resumption of current-flow after an interruption of the same.

4. In a current-interruption indicator, the combination with an indicator-member;- of a thermomotive-member operatively connected to the said indicator-member to actuate the same; an electric heater associated with the said thermomotive-member for normally heating the same; and a latching device for holding the said indicator-member in its current-interruption-indicating position; whereby a change in temperature in the said electric heater will correspondingly affect the said thermomotive-member and cause the same to actuate the said indicatormember when the latter is in non-indicating position.

- 5. A current-interruption indicator as defined in claim 4 and having the elements constructed and arranged to'efiect the movement of the indicator-member by the cooling of the thermomotive member, due to current interruption.

6. A current interruption indicator as defined in claim 4 and having the elements constructed and arranged to eilect the movement 01' the indicator-member by the rise in temperature of the thermomotive-member, as the result of the resumptionoi current-flow after an interruption of the same. I

7. In a current-interruption indicator, the combination with an indicator-member; of a thermomotive-member operatively connected to the said indicator-member to thermomotively move the said indicator-member; an electric motor associated with the said thermomotive-memher for normally heating the same by heat developed by the current flowing therethrough; whereby a change in temperature in the said electric heater will correspondingly affect the said thermomotive-member and cause the latter to thermomotively move the said indicator-memher. i

8. In a current-interruption indicator, the combination with an electric motor; of an indicator-member; a thermomotive-member operatively connected to the said indicator-member to thermomotively move the said indicator-member; an electric heater associated with the said thermomotive-member i'or normally heating the same; and electrical connections between the said electric motor and electric heater of such character that when the current-supply fails to the said motor, the said electric heater will also be deprived of current; whereby a change in temperature in the said electric heater will correspondingly afl'ect the said thermomotive-member and cause the latter to thermomotively move the said indicator-member.

{ 9. A current-interruption indicator as defined in claim 8 and having the elements constructed and arranged to effect the movement of the indicator-member by the cooling of the thermomotive-member, due to current interruption.

10. A current-interruption indicator as defined in claim 8and having the elements constructed and arranged to effect the movement of the indicator-member by the rise in temperature of the thermomotivemember, as the result oi the resumption of current-flow after an interruption of the same.

11. In a current-interruption indicator, the combination with an electric motor; of an indicator-member; a thermomotive-member operatively. connected to the said indicator-member to actuate the same; an electric heater associated with the said thennomotive-member for normally heating the same; electrical connections between the said electric motor and electric heater of such character that when the current-supply fails to thefsaid motor, the said electric heater will also be deprived of current; and a latching device for holding the said indicator-member in its current-interruption-indicating position; whereby a change in temperature in the said electric heater will correspondingly affect the said thermomotive-member and cause the same to actuate the said indicator-member when the latter is in nonindicating position.

12. In an electric clock, the combination with the electric driving-motor thereof and an electric circuit for the said motor; of a dial formed withan aperture an indicator-member having indicia thereon and mounted back of the said dial in position to expose its indicia through the aperture therein; a thermomotive-member operatively connected to the said indicator-member to thermomotively move the said indicator-member; and an electric heater associated with the said thermomotive-member for normally heating the same and connected into the circuit or the said motor for being concurrently electrically energized and deenergized therewith. Y

13. In an electric clock, the combination with the electric driving-motor thereof and an electric circuit for the said motor; of a dial formed with an aperture; an indicator-member having indicia thereon and mounted back of the said dial in position to expose its indicia through the aperture therein; a thermomotive-member operative- 1y connected to the said indicator-member for actuating the same; an electric heater associated with the said thermomotive-member for normally heating the same and connected into the circuit of the said motor for being concurrently electrically energized and deenergized therewith; and a latching device for holding the said indicatormember in its current-interruption-indicating position.

t 14. In an electric clock, the combination with a dial formed with an aperture and an electric motor; of an indicator-member having indicia thereon and mounted back of the said dial in position to expose its indicia through the aperture therein; and a thermomotive-member operatively connected to the said indicator-member to thermomotively move the said indicator-member and associated with the said electric motor for being normally heated by the heat developed by the same.

15. In an electric clock, the combination with a dial formed with an aperture and an electric motor; of an indicator-member having indicia thereon and mounted back of the said dial in position to expose its indicia through the aperture therein; a thermomotive-member operatively connected to the said indicator-member for actuating the sameand associated with the said electric motor for being normally heated by the heat developed by the same; and a latching device for holding the said indicator-member in its current-interruption-indicating position.

16. In an electric clock, the combination with an electric motor therefor; of an electric circuit sioned by a current-change in the said electric 15 circuit.

ELOF L. CARLSON. ARTHUR B. POOLE. 

